Large Image Cut off + part of another showing

If I click on a thumbnail, the large image slides in but only about 3/4 of the way so about 1/4 of another image is showing and the last thumbnail doesn't show any large image. What am I doing wrong (do the images have to be resized ahead of time to a certain size)?

The problem is in CSS (UL or LI margins) but I can't tell you where until I see your site.

I should have included that...here it is:
asis-nj.lunariffic.com/
As you can see I am trying to learn joomla- so it's in the css of the template or this module?

Please add this in CSS file of your template or module: